1. Field of the Invention
This invention relates to improvements in hydraulic steering systems for vehicles, and more particularly, but not by way of limitation, to a dual steering system for substantially precluding loss of steering control of large, off-highway vehicles.
2. Description of the Prior Art
Off-highway vehicles are in widespread use today in many industries wherein large and heavy load conditions exist, such as in open pit mining, large scale construction operations, and the like. The handling of large quantities of material, such as coal, or the like, requires equipment sufficiently heavy or strong to lift and transport the bulky material with substantial ease, and large enough to carry great quantities thereof in order to reduce the time and expense of haulage. As the equipment becomes larger and heavier in design, it will be apparent that the steering system and other operational systems must be designed to overcome greater difficulties. In order to facilitate the steering of these large and heavy vehicles, hydraulic steering systems have been developed. Whereas these systems have increased the ease of steering, there are certain disadvantages in that the systems normally require the use of hydraulic fluid lines in relatively exposed positions. In the event of the rupture or other damage of any of the hydraulic lines, the entire steering system is usually lost. The great size and weight of these vehicles may cause disastrous results upon loss of steering control thereof.